1. Field of the Invention
The present invention relates to a syringe assembly adapted for dispensing and delivery of a fluid. More particularly, the present invention is directed to a pre-filled syringe assembly having a transitionable plunger rod for reducing the overall dimension of the syringe assembly in the collapsed position.
2. Description of Related Art
Syringe assemblies, and in particular hypodermic syringes, are well known in the medical field for dispensing fluids, such as medication. A conventional syringe typically includes a syringe barrel with an opening at one end and a plunger mechanism disposed through the other end. The plunger mechanism typically includes a plunger rod extending through the barrel, with a plunger head or stopper at the end of the plunger rod within the barrel, and with a finger flange at the other end of the plunger rod extending out of the barrel. In use, the plunger rod is retracted through the syringe barrel to aspirate or fill the syringe barrel with a fluid, such as a medication, with the plunger rod extending out from the rear end of the syringe barrel. For delivery of the medication to a patient, the opening of the syringe barrel is adapted for fluid communication with a patient, such as through a hypodermic needle fitted at the front end of the syringe barrel or through a luer-type fitting extending from the front end of the syringe barrel for attachment with a fluid line of a patient. Upon depressing of the plunger rod, the plunger rod and stopper travel through the syringe barrel, thereby forcing the contents of the syringe out through the opening at the front end for delivery to the patient. Such an operation is well known in the medical field, and medical practitioners have become well accustomed to the use of such common fluid delivery procedures through standard syringes.
Conventional syringes are well known to be used in connection with a vial of a medication, wherein the user draws the fluid into the syringe immediately prior to injection and delivery of the fluid to the patient. Oftentimes, hypodermic syringes may be packaged as “pre-filled” devices, wherein the syringe is pre-filled with medication prior to being packaged and delivered to the end user. In this manner, there is no need for the user to fill the device prior to injection, thereby saving time for the end user and maintaining consistent volumes for delivery.
Packaging of such pre-filled syringes, however, tends to be bulky. A pre-filled syringe is typically packaged with the opening at the front end of the barrel including a separate cap thereover and with the plunger rod retracted out of the back end of the syringe barrel, with the fluid pre-filled within the syringe barrel. Such packaging creates an elongated package that can be awkward for shipping and storage.
Pre-filled syringes and pre-filled metered dose syringes are often filled with narcotics or other drugs at a production facility, packaged, and then shipped to a medical facility. Once at the facility, these syringes are often placed in controlled storage and/or locked cabinets to reduce theft of the syringes themselves and/or theft of the contents of these syringes. The space within these controlled storage locations is often limited, thus there is a need for a syringe assembly that has a smaller packaging footprint, to reduce the storage space required for containing the syringe. A smaller packaging footprint is also beneficial for end users who may carry the syringe with them in a pocket, purse or the like. It is also desirable to produce syringes that are uniform in terms of an outer surface shape to allow for stacking of these syringes within the storage cabinet.
Typical pre-filled hypodermic syringes have elongated plunger rods extending from beyond the proximal end of a syringe barrel to move the stopper through an injection cycle within the syringe barrel by linear actuation of the elongated plunger rod. This arrangement increases the length of the packaged syringe assembly, which increases costs associated with packaging the pre-filled syringe and takes up additional storage space.